Dairy calves' discrimination of people based on previous handling.

To determine whether calves can distinguish between different people, we examined their contact with familiar and unfamiliar people and with people who handled them positively or aversively. When a familiar or unfamiliar person entered the calves' pens, latency to contact and duration of contact were the same, but bouts of contact were shorter and more frequent if the person was unfamiliar. In Exp. 2, calves were treated repeatedly in their home pens, by three handlers: one treated them positively, one aversively, and a third (neutral) did not interact with them. After seven treatments, calves tended to avoid all three handlers. After 12 treatments, calves contacted the positive handler significantly more than the aversive handler in their home pens. However, when retested outside their home pens, the calves did not discriminate. In Exp. 3, calves were treated positively and aversively in a novel treatment pen rather than in their home pens. The calves made more contact with the positive handler than the aversive handler after seven treatments. When retested in their home pens, most of the calves continued to avoid the aversive handler, but some made contact with the aversive handler. Calves can readily discriminate between different people based on their previous experience. They can develop a general fear of people as a result of aversive handling, and positive handling is required to overcome this. However, some calves do not generalize their fear of an aversive handler to places other than those in which they were handled.